Presented here is a unified approach to evaluating the error-rate performance of digital communication systems operating over a generalized fading channel. What enables the unification is the recognition of the desirable form for alternate representations of the Gaussian and Marcum Q-functions that are characteristic of error-probability expressions for coherent, differentially coherent, and noncoherent forms of detection. It is shown that in the largest majority of cases, these error-rate expressions can be put in the form of a single integral with finite limits and an integrand composed of elementary functions, thus readily enabling numerical evaluation.

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A unified approach to the performance analysis of digital communication over generalized fading channels

Adaptive linear and decision feedback receiver structures for coherent demodulation in asynchronous code division multiple access (CDMA) systems are considered. It is assumed that the adaptive receiver has no knowledge of the signature waveforms and timing of other users. The receiver is trained by a known training sequence prior to data transmission and continuously adjusted by an adaptive algorithm during data transmission. The proposed linear receiver is as simple as a standard single-user detector receiver consisting of a matched filter with constant coefficients, but achieves essential advantages with respect to timing recovery, multiple access interference elimination, near/far effect, narrowband and frequency-selective fading interference suppression, and user privacy

Adaptive receiver structures for asynchronous CDMA systems

This tutorial describes the transmission, group delay time and quadratic dispersion properties of the four basic building blocs of optical filters built using ring resonators. These building blocs are single-ring resonators in either two-port (all-pass) or four-port (add/drop filter) configuration. The effect of waveguide and coupler loss is included throughout. Explicit expressions to compute the complex amplitude of the circulating wave in the ring, the Q factor, the finesse and the insertion loss are also given. Attention is drawn to the similarities between the ring resonator the Fabry-Pe/spl acute/rot resonator and the Gires-Tournois interferometer. Material properties and fabrication technology are not reviewed.

Transmission, group delay, and dispersion in single-ring optical resonators and add/drop filters-a tutorial overview

Techniques for reducing peak-to-average power in multicarrier transmitters employ peak cancellation with subcarriers that are impaired by existing channel conditions. The use of Carrier Interferometry (CI) coding further improves the effectiveness of peak reduction. CI coding can also be impressed onto pulse sequences in the time domain, which enhances spectral selection and facilitates peak-power control.

Software adaptable high performance multicarrier transmission protocol

We present a unified approach to determine the exact bit error rate (BER) of noncoherent and differentially coherent modulations with single and multichannel reception over additive white Gaussian noise and generalized fading channels. The multichannel reception results assume independent fading in the channels and are applicable to systems that employ post-detection equal gain combining. Our approach relies on an alternate form of the Marcum Q-function and leads to expressions of the BER involving a single finite-range integral which can be readily evaluated numerically. Aside from unifying the past results, the new approach also allows for a more general solution to the problem in that it includes many situations that in the past defied a simple solution. The best example of this occurs for multichannel reception where the fading on each channel need not be identically distributed nor even distributed according to the same family of distributions.

A unified approach to the probability of error for noncoherent and differentially coherent modulations over generalized fading channels

In this paper, we consider a quasi-orthogonal (QO) space-time block code (STBC) with minimum decoding complexity (MDC-QO-STBC). We formulate its algebraic structure and propose a systematic method for its construction. We show that a maximum-likelihood (ML) decoder for this MDC-QO-STBC, for any number of transmit antennas, only requires the joint detection of two real symbols. Assuming the use of a square or rectangular quadratic-amplitude modulation (QAM) or multiple phase-shift keying (MPSK) modulation for this MDC-QO-STBC, we also obtain the optimum constellation rotation angle, in order to achieve full diversity and optimum coding gain. We show that the maximum achievable code rate of these MDC-QO-STBC is 1 for three and four antennas and 3/4 for five to eight antennas. We also show that the proposed MDC-QO-STBC has several desirable properties, such as a more even power distribution among antennas and better scalability in adjusting the number of transmit antennas, compared with the coordinate interleaved orthogonal design (CIOD) and asymmetric CIOD (ACIOD) codes. For the case of an odd number of transmit antennas, MDC-QO-STBC also has better decoding performance than CIOD.

Quasi-orthogonal STBC with minimum decoding complexity

In this paper, we consider a quasi-orthogonal (QO) space-time block code (STBC) with minimum decoding complexity (MDC-QO-STBC). We formulate its algebraic structure and propose a systematic method for its construction. We show that a maximum-likelihood (ML) decoder for this MDC-QOSTBC, for any number of transmit antennas, only requires the joint detection of two real symbols. Assuming the use of a square or rectangular quadratic-amplitude modulation (QAM) or multiple phase-shift keying (MPSK) modulation for this MDC-QOSTBC, we also obtain the optimum constellation rotation angle, in order to achieve full diversity and optimum coding gain. We show that the maximum achievable code rate of these MDC-QOSTBC is 1 for three and four antennas and 3/4 for five to eight antennas. We also show that the proposed MDC-QOSTBC has several desirable properties, such as a more even power distribution among antennas and better scalability in adjusting the number of transmit antennas, compared with the coordinate interleaved orthogonal design (CIOD) and asymmetric CIOD (ACIOD) codes. For the case of an odd number of transmit antennas, MDC-QO-STBC also has better decoding performance than CIOD.

Quasi-Orthogonal STBC With Minimum Decoding Complexity

In this paper, we formulate the algebraic structure of quasiorthogonal STBC with minimum decoding complexity (MDC-QOSTBC), whose maximum likelihood (ML) decoder only requires the joint detection of two real symbols, for any numbers of transmit antennas. We also propose a systematic method to construct an MDC-QOSTBC from an Orthogonal-STBC (O-STBC). The maximum code rate of the resultant MDC-QOSTBC is shown to be the same as that of the lower-order O-STBC used to construct it. We also find the optimum constellation rotation angle for the proposed MDC-QOSTBC construction to achieve full diversity and optimum coding gain. We can show that the proposed MDC-QOSTBC has more even power distribution over the transmit antennas, better scalability in adjusting the number of transmit antennas, and more superior decoding performance than the coordinate interleaved orthogonal design (CIOD) and asymmetric CIOD

Construction of quasi orthogonal STBC with minimum decoding complexity

A Quasi-Orthogonal Space–Time Block Code (QO-STBC) is attractive because it achieves higher code rate than orthogonal STBC and lower decoding complexity than non-orthogonal STBC. In this paper, we first derive the algebraic structure of QO-STBC, then we apply it in a novel graph-based search algorithm to find high-rate QO-STBCs with code rates greater than 1. From the four-antenna codes found using this approach, it is found that the maximum code rate is limited to 5/4 with symbolwise diversity level of four, and 4 with symbolwise diversity level of two. The maximum likelihood decoding of these high-rate QO-STBCs can be performed on two separate sub-groups of symbols. The rate-5/4 codes are the first known QO-STBCs with code rate greater 1 that has full symbolwise diversity level.

On the Search for High-Rate Quasi-Orthogonal Space–Time Block Code

Approximate results for the bit error probability (BEP) of binary phase shift keying (BPSK) in the presence of a noisy carrier phase reference are presented. The results show correctly the behavior or the BEP as a function of SNR. The accuracy of the approximations is verified by simulations and numerical integration of the BEP formulas. The results are compared with existing bounds. >

Tjeng Thiang Tjhung

Papers

Quasi-orthogonal STBC with minimum decoding complexity

Quasi-Orthogonal STBC With Minimum Decoding Complexity

Construction of quasi orthogonal STBC with minimum decoding complexity

On the Search for High-Rate Quasi-Orthogonal Space–Time Block Code

Approximate results for the bit error probability of binary phase shift keying with noisy phase reference